It has been decided. The United States of America will no longer be a party to the Paris Agreement. Climate deniers finally have found their white knight in the personification of the president of the United States, Donald Trump. Case closed.

Except it’s not.

From average citizens to CEOs, the American people have been saying to the world, “This matters to us and we are committed.” From the Make America Great Again City of Pittsburgh to the Socialist State of California, political leaders have been saying, “We are part of this world, and we will do the right thing.”

Today, Sen. Joni Ernst has the chance to truly stand strong against Mr. Trump and be one of those leaders — and she can do so in the name of stimulating economic growth in our rural communities and ensuring a better world for our children. She can choose to stand with rural Americans fighting hard to create a new energy independent economy rather than side-by-side with Syria.

In September 2016, nearly 200 countries, including the United States and China, ratified the historic Paris Agreement. This agreement requires each of the participating countries to enact a plan to cut its emissions and then reconvene every five years to raise those standards and publicly disclose progress. Yet, Mr. Trump, it appears, has decided to withdraw the U.S. from this pact.

The agreement is crucial to the lives of Americans because, on the global scale, climate change is a national security threat. The Department of Defense even describes climate change as a “threat multiplier” because it makes the jobs of our men and women in uniform harder. For instance, more frequent extreme weather events mean a greater strain on the United States military’s logistical supply lines, which are crucial in times of war. Droughts and resource shortages end up strengthening the very extremist groups our troops face on the battlefield because of the breakdown of fragile governments’ ability to deliver services. In places like Iraq and Afghanistan where our troops are trying to empower local government, we might as well lock a ball and chain around their ankles.

Essentially, if we don’t take steps to move away from fossil fuels of the past and toward clean energy of the future, we only make all of these problems worse and further risk the lives of those in uniform.

Taking these steps requires effort from everyone (including other big polluters similar to us, like China and India) to effect real change. That is the whole point of an agreement like the one that came out of Paris: every country — big or small, rich or poor — has to pull their weight. Creating a system of accountability that requires all countries to share their progress with the world will let us know who is doing their part. And the fact that China ratified the agreement alongside us and then India followed shortly thereafter shows serious commitment from all sides.

To take to a more local perspective on this, the Paris Agreement provides a great opportunity to revitalize the American farm economy — as attested to by the National Farmers Union, of which Iowa is a part. In mid-April, NFU wrote Mr. Trump a letter asking him to maintain the United States’ commitment to the agreement.

In the letter, the NFU states that the Paris Agreement will increase employment opportunities, stimulate economic growth in rural communities, and create new sources of revenue that will give young people a reason to stay on farms and in small towns — small towns like the ones Sen. Ernst and I grew up in. The focus on energy efficiency will also prompt lower power costs for producers and rural businesses, which given Sen. Ernst’s placement as the chair of the Subcommittee on Jobs, Rural Economic Growth, and Energy Innovation, should make sense.

Sen. Ernst, by defending the Paris Agreement, you will be defending many Iowan livelihoods. The agreement provides a route away from the misfortunes farmers have faced due to climate change — such as frequent and intense drought, flooding and wildfires — and toward more profitable and secure means of income. After all, the work that our nation must do to meet the standards of the agreement will stimulate growth in the farm economy and create more jobs in the clean energy industry both now and in the years ahead.

Sen. Ernst, you have the opportunity to ensure not only more employment opportunities but also a safer, more secure world for our children.

Jonathan Freeman is Fairfield resident and a Fellow with Truman National Security Project who recently completed his doctoral dissertation at London School of Economics. He deployed to Iraq and Afghanistan as an Army officer, as well as served in the Obama Administration at DoD and USAID. Follow him on Twitter @JFonIR.